1. Field of the Invention
This invention relates to a door lock assembly, more particularly to a door lock assembly which includes an inner handle provided with a press button.
2. Description of the Related Art
FIG. 1 shows a door lock assembly which is disclosed in U.S. Pat. No. 5,301,526. The outside lock unit of the door lock assembly includes an outer handle (E′) and an outer drive tube (C′) The outer drive tube (C′) has one end inserted into the outer handle (E′). A key-operated lock (C′) is mounted inside the outer handle (E′) and the outer drive tube (C′). The inside lock unit includes an inner handle (H′) and an inner drive tube (I′) inserted into the inner handle (H′). A rotary button (F′) is disposed inside a space defined by the inner handle (H′) and the inner drive tube (I′). A latch-operating tube 1 is connected between the inner and outer handles (H′) and (E′) for latching or unlatching a door latch (not shown).
The latch-operating tube 1 has a tubular member of rectangular cross-section and has an enlarged base (not shown) which has a push protrusion (not shown). The latch-operating tube 1 is inserted into the inner drive tube (I′), whereas the enlarged base thereof extends into the outer drive tube (C′). A limit plate (2e) is mounted inside the outer drive tube (C′) and is formed with a slot (not shown). A rotary button rod 3 has one end connected to the key-operated lock (G′) and the other end extending into the rotary button (F′). The rotary button rod 3 extends through the limit plate (2e) and the latch-operating tube 1 between the key-operated lock (G′) and the rotary button (F′).
When the rotary button (F′) is turned, the rotary button rod 3 pushes the limit plate (2e) to project outwardly from the outer drive tube (C′) so that the door lock assembly is in a locked state. The door lock assembly is placed in an unlocked state when the key-operated lock (G′) is unlocked using a key to turn the rotary button rod 3 so that the limit plate (2e) is moved inward, or when the inner handle (H′) is rotated to turn the latch-operating tube 1 so as to push the limit plate (2e) inward and to thereby turn the rotary button rod 3. Such a door lock assembly tends to cause inconveniences to a handicap as it is necessary to rotate the rotary button (F′).
Door lock assemblies having an inner lock unit provided with a press button have existed in the prior art. Examples of such door lock assemblies are disclosed in U.S. Pat. Nos. 5,816,086 and 6,623,053. However, while the press buttons disclosed therein can be operated through a pressing action, the constructions thereof are complicated.